Transtracheal Doppler in infants and small children following surgery for congenital heart disease: Rational use of an improved technology

To compare measurements of cardiac output utilizing an improved transtracheal Doppler technology with measurements obtained using two-dimensional echocardiography. DESIGN:Prospective, descriptive study. SETTING:Cardiovascular intensive care unit at a university medical center. PATIENTS:Fourteen children ranging in age from 14 days to 3 yrs (mean 1.3 ×.97 yrs) following surgery for complex congenital heart disease. INTERVENTIONS:Simultaneous cardiac output determinations using transtracheal Doppler and two-dimensional echocardiography were compared. Cardiac output was determined using measurement of blood velocity and diameter of the ascending aorta following surgery. Direct aortic diameter measurements made at operation were compared with measurements obtained by transtracheal Doppler, two-dimensional echocardiography and angiography. RESULTS:The mean difference in aortic root diameter between measurements made directly at operation and transtracheal Doppler was 5%, compared with 13% by two-dimensional echocardiography, and 21% by angiography, a significant difference by analysis of variance (F[3,31], p < .007). Post hoc comparisons demonstrated significant (p < .05) differences between echocardiography and angiographic aortic diameters. The mean difference between transtracheal Doppler and echocardiographic determination of cardiac output was 10.9% (t[10] = −1.37, p = .007). CONCLUSIONS:An improved transtracheal Doppler technology compares favorably with echocardiographic determination of cardiac output in infants and young children. This improved technology may provide a useful means to assess cardiac output and may allow titra-tion of therapy in critically ill infants and children. (Crit Care Med 1994; 22:1294–1300)